Hello, Ive been reading several posts that look like the same problem as mine but there always about the power supply, this is not the case for me. Here are my specs befor i get into this, my motherboard is a AN35N-Ultra/nvidia nforce 2 400ultra, 80gig HD, CD/DVD-rom, 512ram, and a really old video card. i would tell u the name of the card but my computer wont start. ok so here is what happend, i was playing a game and everything was fine, i exited the game normally and then hit the power button on the pc. it was kinda odd because everytime i hit the button it goes through a shutdown routine, this is not what happend this time. i hit the button and the pc just went off. i didnt really think anything of it so i left for a few hours. when i come back to turn it on nothing happend, so i turned off the power switch in the back and waited for all the lights to go out inside the computer. i then flip the switch back on and the computer starts up but then about 5 seconds later it goes dead. the only thing thats left on inside is the internet lights in the back but there always on. i have tried replacing the power supply, unpluging everything the HD the CD the video card and nothing happends it always shuts down after about 5 seconds. I really need some help and anything you guys have to say would be great, if u need to know any info about the problem that i may have missed just say so ill do my best in getting it for you.